Electro-optical devices which enable people such as soldiers, aviators, sailors, and sportsman to view objects at night and in other low light conditions are commonly referred to as night vision devices. Night vision devices were originally developed for military applications. However, night vision devices are now being marketed to the general public. Commercially available night vision devices are becoming quite common for use in activities that take place in low light conditions. Such activities include night marine piloting, underwater vision, night security surveillance, hunting, fishing, and navigation.
Examples of some commercially available night vision devices and the technology associated therewith are described in U.S. Pat. No. 08/152,193 entitled MONOCULAR NIGHT VISION DEVICE filed on Nov. 13, 1993 and U.S. Pat. No. Des. 29/014,252 entitled NIGHT VISION MONOCULAR filed on Oct. 15, 1993, both applications being assigned to the ITT Corporation the assignee herein. Each of these applications relate to monocular night vision devices.
Other types of commercial night vision devices are described in U.S. patent application Ser. No. 08/108,989 entitled NIGHT VISION BINOCULARS filed on Aug. 18, 1993 and U.S. patent application Ser. No. 07/954,006 entitled CONSUMER NIGHT VISION APPARATUS filed on Sep. 30, 1992. Both of these applications are assigned to the ITT Corporation the assignee herein.
Most night vision devices utilize an image intensifier that receives very small quantities of both visible light and non-visible near infrared light reflected off objects on the ground and amplifies these very small quantities of light into a clearly visible light. The visible and non-visible near infrared light reflected by these objects originate from the light radiated by the moon and stars of the night sky. In most situations, the night sky provides sufficient quantities of light for the night vision device to operate effectively. However, there are many situations particularly, during the dead of night when there are insufficient quantities of visible and near infrared light available to effectively operate the night vision device.
The prior art has responded to this problem by providing flashlight-like devices which illuminate the objects to be view with a beam of non-visible near infrared light. Accordingly, the light energy reflected from the object will be visible through the night vision device although it will not be visible to the naked eye.
In order to free-up the user's hands for other activities, these prior art illuminator devices are usually attached to the night vision device. An example of such an arrangement is described in U.S. patent application Ser. No. 08/215,512 filed on Mar. 22, 1994 entitled ILLUMINATOR BRACKET FOR A NIGHT VISION DEVICE, assigned to ITT Corporation the assignee herein.
A typical prior art flashlight illuminator device employs a conical-shaped reflector oriented behind the light source to provide a forward focused pattern of light around the target object. The light pattern provided by such an arrangement is usually uneven in brightness with on and off-axis bright spots. The uneven brightness and on and off-axis bright spots are caused by imperfections in the surface of the reflector. Inconsistent light patterns are lower in overall light intensity which hampers the identification of the target object to be viewed with the night vision device.
It is, therefore, a primary object of the present invention to provide an improved night vision flashlight illuminator device which provides a much brighter and evenly focused light beam pattern.
It is another object of the present invention to provide a night vision flashlight illuminator device which allows continuously variable beam diameters from spot to wide angle.